This study used the Montague-Riley Test to introduce a new scoring procedure that revealed errors in cognitive processes occurring at subcomponents of an electricity problem. The test, consisting of four parts with 36 open-ended problems each, was administered to 250 high school students. A computer program, ELTEST, was written applying a decision-table strategy to locate requested unknown variables. The program generated the right answer consecutively for an unknown variable and solved it at each step, using conditions determined by the previous step. If the generated response did not match a student's answer, then the program: (1) printed the location of the component as well as the conditions used at the current step; and (2) picked up the student's wrong response and made it one of the conditions in solving the next unknown variable. Component scoring made it possible to identify where an error was made, and a remediation scheme for a particular error could follow. Scoring can be evaluated by (1) examining sources of variations of scoring and the meaningfulness of these variations, and (2) composing item by item correlation matrix of component scoring and regular scoring. (LMO)